Dismountable furniture, particularly shelving and wall systems, usually incorporate a plurality of vertical and horizontal panels, and some form of releaseably interlockable junction means. The success of the particular design turns almost entirely on the design of the junction means. In the majority of cases some form of metallic hardware is provided in the vertical members and in the horizontal members, so that the two may be interlocked. Usually, a tool such as a coin, or a simple screwdriver is required in order to rotate one or other or both of the locking means into a locked position.
In some such systems, the vertical members are made up in several sections, and each section is separated from the next section by means of a separate locking member, so that in fact each vertical member is a composite of two or even three such vertical sections.
A wide variety of different locking systems have been used in the past, but they have all exhibited various limitations. For example, in some cases the security of the locking system was inadequate, and the structure could never be made completely rigid. In other cases, particularly where a separate locking member is used between adjacent vertical portions, the shelving system exhibited relatively unsightly, or at least obvious, discontinuities in the vertical members which placed severe limitations on the type of furniture which could be designed using such a system. In other such locking systems, the design of the individual members was relatively costly, and also involved costly machining of the various vertical and horizontal members to accommodate the locking system.
Another and more fundamental disadvantage of most earlier systems is the fact that the locking devices must be manually tightened up before any articles such as books, papers, or art objects, tableware and the like, can be placed on the shelving. Once the shelves are loaded however it is a common experience that the locking devices then become somewhat loosened, or at least placed under different stresses, so that the entire furniture system becomes loosened. It is then necessary to attempt to retighten the various locking devices by hand. At this stage, however, such retightening is extremely different if not hazardous, and may mean removing a large portion of the contents of the furniture or shelving system.
Similarly, in the case of for example a book shelf, where books are repeatedly removed and replaced, the movement of the books may in itself lead to a gradual loosening or slackening of the locking system.